Altered Immunophenotypes on Leukemic and/or Monocytic Cells from Acute Myeloid Leukemia Highly Predict for Nucleophosmin Gene Mutation

Introduction. Nucleophosmin gene mutation (NPM1mut) occurs in around 30% of acute myeloid leukemia (AML) patients, frequently linked with favourable prognosis in the absence of FLT3-ITDmut, which occurs in around 40% of NPM1mut AML. Therefore, more expeditious diagnostic approaches may contribute to early diagnosis and prognostic stratification of these patients. Herein, we investigated the association of immunophenotypic features of leukemic and monocytic cells with the presence of NPM1mut in AML. Methods. A total of 404 bone marrow (BM) samples from newly-diagnosed AML patients according to WHO 2017 classification were retrospectively studied by 8-color flow cytometry, including 225 AML with NPM1mut and 179 cases wild type gene (NPM1wt). Information on FLT3-ITD could be obtained from 397/404 cases. Thus, FLT3-ITDmut was present in 85/397 (21%), being concomitant with NPM1mut in 62/85 AML cases (73%). Logistic regression analysis was used to identify predictive phenotypes for the presence of NPM1mut. Results. Overall, blast cell with immunophenotypic features of monocytic differentiation (corresponding to FAB M4 and M5 AML subtypes) were observed among 135/225 (60%) and 69/179 (38.5%) AML patients with NPM1mut and NPM1wt, respectively (p